Disposition of Gamma-Hydroxybutyric Acid in Conventional and Nonconventional Biologic Fluids After Single Drug Administration: Issues in Methodology and Drug Monitoring
Sergio Abanades, Magı́ Farré, Mireia Segura, Simona Pichini, Antoni Pastor, Roberta Pacifici, Manuela Pellegrini, Rafael de la Torre
Therapeutic Drug Monitoring February 1, 2007 DOI: 10.1097/ftd.0b013e3180307e5e via OpenAlex
Summary
After a single oral dose of 50 mg/kg sodium GHB, mean peak plasma concentrations reached 83.1 μg/mL at 30 minutes, then declined to 0.9 μg/mL at 6 hours. GHB appeared in oral fluid at levels one-third to one-fourth of plasma concentrations, with a half-life of about 1.2 hours compared to 0.7 hour in plasma. Less than 2% of the dose was excreted in urine, and sweat contained only low concentrations. Subjective effects followed a mixed sedative-stimulant pattern, peaking between 1 and 1.5 hours and lasting 2 hours, and were related to plasma concentrations. Oral fluid and sweat were not suitable for monitoring GHB consumption.
Study at a glance
| Characteristics | Controlled pharmacokinetic study Peer reviewed |
|---|---|
| Sample size | 5 |
| Population | Healthy volunteers |
| Intervention | Sodium GHB |
| Dose | 50 mg/kg |
| Keywords | Pharmacokinetics Pharmacology Chemistry Sedative Oral administration |
| Citations | 66 |
| Key finding | Oral fluid and sweat are not suitable matrices for monitoring GHB consumption, and GHB subjective effects correlate with plasma concentrations. |
Abstract
Little controlled drug administration data are available to aid in the interpretation of gamma-hydroxybutyric acid (GHB) distribution in conventional and nonconventional fluids and the potential correlation between the pharmacokinetics of GHB and drug effects. Single oral sodium GHB doses of 50 mg/kg were administered to five volunteers. Plasma, oral fluid, urine, and sweat were analyzed for GHB by gas chromatography-mass spectrometry. GHB stability in plasma was studied at different storage temperatures. Subjective effects were measured using a set of 13 different visual analog scales. Mean peak GHB plasma concentrations at 30 minutes were 83.1 microg/mL. After the absorption phase, concentrations declined to mean values of 0.9 microg/mL at 6 hours. GHB was found in oral fluid at peak value concentrations equivalent to one third to one fourth of those found in plasma. The oral fluid-to-plasma ratio varied two fold in the 1- to 6-hour time range but always was lower than unit. The mean half-life (t1/2) of GHB was approximately 0.7 hour in plasma and approximately 1.2 hours in oral fluid. GHB urinary excretion is less than 2% of the dose administered. GHB was also detected in sweat at low concentrations. GHB showed a mixed sedative-stimulant pattern with subjective effects peaking between 1 and 1.5 hours after drug administration and lasting for 2 hours. Oral fluid and sweat appeared not to be suitable biologic matrices for monitoring GHB consumption. GHB-mediated subjective effects are related to GHB plasma concentrations.